A study states that music on YouTube hinders piracy

It has been shown that YouTube actually reduces music piracy, as proven through research of exclusive YouTube data along with a survey of thousands of users in a variety of countries.
The researchers discovered that if music were not available on YouTube users would be forced into using music channels of lesser value, and that means piracy websites too.
“Without YouTube, 85% of time spent listening to YouTube would be lost  or shifted to lower or similar value channels”, the study says.

Source: RBB Economics (PDF).